1. Field of the Invention
The present invention relates to a gas pressure-reducing valve and, more particularly, to a gas pressure-reducing valve in which a valve member to be seated on a valve seat having a valve hole opened at its central portion and leading to a pressure-reducing chamber between a body and a diaphragm is fixed on a valve stem connected to the central portion of the diaphragm and is disposed coaxially with the valve axis.
2. Related Art
Such a gas pressure-reducing valve has already been known in the prior art from Japanese Patent Application Laid-open Nos. 3-260483 and 8-334182 and the like.
In the gas pressure-reducing valve disclosed in the above Japanese Patent Application Laid-open No. 3-260483, a valve seat is formed on the inner end of an accommodation bore that is formed in a body for accommodating a valve member, and a cover member for sealing the outer end of the accommodation bore is mounted on the body. Not only the number of parts is large, but also a cover and the mentioned cover member have to be attached to both sides of the body, and hence the degree of freedom for arranging the gas pressure-reducing valve in the body is narrowed.
In the gas pressure-reducing valve disclosed in Japanese Patent Application Laid-open No. 8-334182, on the other hand, a valve body to be screwed in a mounting bore formed in a body is constructed to have a valve seat and to accommodate a valve member. This construction is also troubled like Japanese Patent Application Laid-open No. 3-260483 by the increased number of parts and the narrowed degree of freedom for arranging the gas pressure-reducing valve in the body.